text: These dosage forms are commonly used to deliver drugs to the eye and nasal cavity. They often include mucoadhesive polymers to improve retention on dynamic mucosal surfaces. Some advanced eye drop formulations may also turn from a liquid to a gel (so called in situ gelling systems) upon drug administration. For example, gel-forming solutions containing Pluronics could be used to improve the efficiency of eye drops and provide better retention on ocular surfaces.